You're right, abusing lag and glitches is considered game disruption, but so are a lot of other things. Here's the in-game definition of disruption found inside the Info Kiosk,

"Interfering with the various events going on in-game. This takes many forms. It can include impersonating staff, intentionally abusing lag, spamming reports, or abusing glitches".

An example which doesn't involve lag would be if a player manged to wedge themself in the entrance to swamp tower and spam their sword outward. Another example would maybe be someone who repeatedly queues up in spar and just runs away until the spar times out, at least in my opinion.